Deflectable implantation device and method of use

ABSTRACT

Systems, apparatus, components and methods are disclosed that allow the clinician to circumvent the pubic arch in instances where it interferes with insertion of instrumentation into the prostate or periprostatic tissue. The systems, apparatus and components disclosed herein employ structures, such as needles and trocars, of shape memory alloys, such as nickel-titanium (Ni—Ti) for the purpose of avoiding the pubic arch when accessing the prostate from the perineum.

CROSS-REFERENCES TO RELATED APPLICATIONS

[0001] This application claims priority from and is related to U.S.Provisional Patent Applications, Serial Nos. 60/285,959, filed Apr. 24,2001, entitled: Deflectable Implantation Device And Method For Use, and60/301,031, filed Jun. 26, 2001, entitled: Deflectable Trocar withCannula And Stylet For Brachytherapy And Method For Use, both of theseprovisional applications incorporated by reference herein.

TECHNICAL FIELD

[0002] This disclosure relates to a medical device for implantation oftreatment elements, such as radioactive seeds and spacers, into livingtissue. Specifically, it relates to shape-memory instruments, such asneedles and trocars, that allow users to bypass obstructions in theinstrument's path.

BACKGROUND

[0003] Since 1983, when Holm published his technique for transperinealinterstitial implantation of radioactive seeds into the prostate (J Urol1983; 130:283-6), prostate brachytherapy has grown into an industry.Selected prostate cancer patients are now routinely counseled regardingbrachytherapy as a treatment option. By virtue of the fact that morethan 30% of newly diagnosed cancers in men arise in the prostate,prostate brachytherapy has become an important procedure. Certaintechnical aspects of the procedure, such as radiation dosimetry andultrasound technology, have improved and/or are better understood thanin 1983. However, the implant needles upon which physicians rely todeliver radiation to the prostate have not kept pace. This is becausedevices and techniques are unable to overcome pubic arch interference,the most common problem facing the prostate brachytherapist.

[0004] As shown in FIG. 1, a substantial portion of the prostate gland10, typically the anterolateral portion of the prostate 10 a, shown bythe x's, (from the clinician's perspective, looking towards the supinepatient's head from below), may sit behind the pubic arch 11. This pubicarch 11 is formed by the convergence of the right 12 and left 13 pubicbones at the midline. This pubic arch 11 is closer to the perineum 14,than the prostate 10. The rectum 15 is located posteriorly.

[0005] Standard prostate brachytherapy is performed with the patientsupine in the lithotomy position. As shown in FIG. 2A, the patient'slegs (not shown) are suspended in stirrups. A needle 16 is employed, anda rectangular template (template grid) or needle guide 17 is placedagainst the perineum 14. The needle guide 17 rests on a support, whichholds an ultrasound probe (not shown) that is inserted into the rectum15. This ultrasound probe permits visualization of the prostate 10during the procedure. The ultrasound support, in turn, rests on a standor brace that is locked in place during the actual implant so that theultrasound probe can be moved forward and back in relation to a definedposition in space.

[0006] The needle guide 17 has a parallel array of holes extendingtherethrough, for accommodating the needle 16. These holes areperpendicular to the template's vertical surface. Once the prostatevolume and location have been confirmed on step section ultrasoundplanimetry, implant needles 16 are guided through the appropriate holesin the template 17 to the desired location within or around the prostate10 in order to fulfill the brachytherapy plan.

[0007] However, as shown in FIG. 2A, the needle 16, as inserted throughthe needle guide 17, may not reach the target prostate area 10 a, as itencounters the pubic arch 12. This is known as pubic arch interference,and may arise from patient positioning, patient anatomy or operatorequipment orientation.

[0008] Pubic arch interference is frequently an insurmountable obstaclefor even the most experienced brachytherapist. Needle displacement orblockage by bone can lead to significant loss of radiation dose coverageof the prostate. In one published series, Peschel from Yale Universityreported that 25% of his patients had pubic arch interference whichdisrupted the implant plan and drastically lowered disease-free survivalrates at four years post implant (J Brachyther Intl 1998; 14: 197-8).Similarly, Wallner from Memorial Sloan-Kettering reported thatapproximately 20% of his patients were at risk for prostate glandunderdosage because of bone interference (Wallner, J Urol 1991;146:90-5).

[0009] Nearly all patients with localized prostate cancer could becandidates for integration of prostate brachytherapy into theirtreatment protocol. It is typically administered as the sole form ofradiation therapy, or can be given in conjunction with external beamradiotherapy. However, some patients are precluded from undergoingprostate implantation for technical reasons. Chief among thecontraindications is pubic arch interference.

[0010] Pubic arch interference is highly variable between patients, andis only loosely related to the size of the gland. Patients with a verysmall pelvic inlet may be difficult to implant despite a small glandvolume. Conversely, patients with a large pelvic inlet may be easy toimplant despite a large gland volume. The overriding issue is whetherthe pubic arch extends beyond the lateral and anterior margins of theprostate gland. If so, then it becomes extremely challenging, andsometimes impossible, to insert needles into the shielded regions of theprostate.

[0011] As stated above, pubic arch interference can be assessed viaComputerized Tomography (CT) or ultrasound scan prior to the implantprocedure in order to determine whether the pelvic bones might impedeneedle insertion. The largest prostate cross-section is overlaid on thenarrowest section of pubic arch, and the overlap is measured. A rule ofthumb is that if more than 25%, or one centimeter, of the prostatecross-section is blocked, the odds of achieving a successful implant arequestionable (Bellon, IJROBP 1999; 43:579-81). The AmericanBrachytherapy Society conducted a survey among brachytherapists andlearned that prostate size greater than 60 grams was felt to be arelative contraindication to prostate brachytherapy alone (Nag, JBrachyther Int 1997; 13:243-51). It subsequently published consensusguidelines for clinicians recommending that implanting glands largerthan 60 grams should not be attempted by novice brachytherapists becauseof the technical difficulties caused by pubic arch interference (Nag,IJROBP 1999; 44:789-99).

[0012] The seasoned brachytherapist can employ several maneuvers uponencountering pubic arch interference in order to skirt the pelvic bonesand circumvent the pubic arch. This type of troubleshooting would permitimplanting of the shielded portions of the prostate, thereby preservingthe intended radiation dose distribution. The most basic maneuver, asshown in FIG. 2B involves withdrawing the needle and reinserting it intoa neighboring hole in the needle guide 17. Here, the needle 16 reachesthe prostate 10. Brachytherapy of the contacted portion of the prostate10 is now possible, but the anterolateral portion of the prostate 10 a,is left untreated or insufficiently treated.

[0013] Alternately, in this situation, the clinician can also slightlyredirect the needle 16 using the bevel on the needle tip to cause theneedle to diverge towards the desired location. If necessary, the needle16 may be diverted after it has passed through the needle guide 17, butbefore it has entered the patient in a further effort to achieve thedesired targeting. The needle tip 16 a can be bent to deflect the needletowards the target location, but this can make it difficult to push theseed sources through, once the desired location is reached.

[0014] Repositioning the patient in an extended lithotomy posture,whereby the legs are drawn closer to the patient's head, can expand thespace between the prostate and the pubic arch enough to allow accurateneedle placement. The orientation of the template, in relation to thepatient's perineum, can be modified by tilting the ultrasound support inan effort to bypass the obstructing bone. However, both of these methodsmay present severe discomfort or the potential for injury to thepatient.

[0015] Finally, freehand needle placement can be attempted using variousangles by removing the template grid. Again, this procedure still runsthe risk of pubic arch interference.

[0016] Most brachytherapists have adopted the technique of modifiedperipheral seed source loading in order to minimize central high doseareas in the prostate. This has been done to protect the urethra. Thisstyle of seed implantation relies heavily on accurate seed placement inthe outer portions of the prostate gland to generate the prescribedradiation dose. Therefore, avoidance of pubic arch interference iscritical if one is to achieve a successful implant.

[0017] While pubic arch interference presents one of the greatestdifficulties in brachytherapy, other factors also contribute todegradation of the intended dose during the implant procedure. Theseinclude patient motion, instability of the ultrasound stand or brace,poor ultrasound image quality, needle divergence, seed settling ormigration, and misplacement of seeds in the bladder or rectum.

[0018] U.S. Pat. Nos. 2,269,963 (Wappler), 4,700,692 (Baumgartner),5,242,373 (Scott), 5,860,909 (Mick), 5,928,130 (Schmidt), and 6,007,474(Rydell) reflect devices that are employed to implant radioactive seedsinto tissue. None addresses the problem of pubic arch interference. Noneof the implant needles currently available, including those described inU.S. Pat. Nos. 5,938,583 (Grimm) and 6,210,315 (Andrews), or thosemarketed by Mentor, Mick (MTP-1720-C, MTP-1820-C), Med-Tec(MT-BRACHYTHERAPY-5001-25, MT-BRACHYTHERAPY-5051-25), Best(Flexi-needle), Bard (BrachyStar®), or MD Tech offer a solution to theproblem. The prostate stabilization needles in U.S. Pat. No. 4,799,495(Hawkins) used during prostate brachytherapy to immobilize the gland donot help the brachytherapist avoid the pubic arch. Neither the real timebrachytherapy spatial software registration and visualization systemoutlined in U.S. Pat. No. 6,129,670 (Burdette), nor the prostatebrachytherapy software planning engine recently described in U.S. Pat.No. 6,200,255 (Yu), provides a solution to pubic arch interferencedespite a sophisticated approach to seed implantation. Finally, in U.S.Pat. No. 6,027,446 (Pathak), there has been devised a method forassessment of pubic arch interference, but has not offered a remedy.

[0019] There is a substance in current use in medicine which possessesproperties that, when adapted to brachytherapy, may be exploited toovercome pubic arch interference. Nickel-titanium alloys, commonly knownas Nitinol®, show a very pronounced shape memory and superelasticeffect. Shape memory characteristics allow it to stay in a deformedshape until heated, whereupon it returns to its pre-deformed shape. Forexample, a surgical hook may be deformed into a straight configurationat room temperature and recover its hooked shape upon introduction totissue, which is above room temperature. The superelasticcharacteristics of Nitinol® allow a hook to be constrained within astraight cannula during insertion into tissue, only to immediatelyregain its curved shape upon deployment into the tissue. Recovery of itsoriginal shape during unloading is the unique aspect of nickel-titaniumalloys that is responsible for its integration into many medicalinventions, eg. U.S. Pat. Nos. 5,000,912 (Bendel), 5,011,473 (Gatturna),5,219,358 (Bendel), and 6,033,404 (Melzer).

SUMMARY

[0020] The systems, apparatus, components and methods disclosed hereinimprove on the conventional art, as they allow the clinician tocircumvent the pubic arch in instances where it interferes withinsertion of instrumentation into the prostate or periprostatic tissue.The systems, apparatus and components disclosed herein employ structuresof nickel-titanium alloys for the purpose of skirting impediments tobrachytherapy needle insertion by taking advantage of its shape memoryand/or superelastic characteristics.

[0021] There is disclosed an improved brachytherapy implantation deviceand accompanying method, that is a combination instrument comprising asleeve, a nickel-titanium needle, and a seed insertion stylet. Thesleeve element has a slightly larger diameter than the nickel-titaniumneedle, and the nickel-titanium needle in turn has a slightly largerdiameter than the seed insertion stylet. The needle and seed insertionstylet can be deployed from their sleeve, causing the needle to assumeits prior shape as it is inserted into the prostate. The needle willthus circumvent an obstruction by arching around it. Upon withdrawal ofthe seed insertion stylet from the needle, a single seed or multipleseeds are entered into the needle at its hub end and propelled forwardwith the seed insertion stylet to the needle tip. As the needle andsleeve are withdrawn from the prostate, the stylet is held in positionrelative to the needle and sleeve, and the seed or seeds are depositedin the desired location beyond the pubic arch obstruction.

[0022] An embodiment disclosed is directed to a medical device having anelongated sleeve with a distal end and a proximal end, a needleslideable within the elongated sleeve, the needle including a distalsegment, and at least a portion of the distal segment slideable beyondthe distal end of the elongated sleeve. The needle is formed of a shapememory material, and the distal segment of the needle has a preformedshape trained into it, for example, a curved shape, such that it assumesthe preformed shape upon being slid beyond the distal end of theelongated sleeve, when in the body.

[0023] Another embodiment disclosed is directed to a medical devicehaving an elongated sleeve with a distal end and a proximal end. Aleading member, for example, a needle with a central bore or a trocar,is slideable within the elongated sleeve. This leading member includes adistal segment, with at least a portion of a distal segment slideablebeyond thee distal end of the elongated sleeve. The leading member isformed of a shape memory material, and the at least a portion of thedistal segment of the leading member has a preformed shape trained intoit, for example, a curved shape, such that it assumes the preformedshape upon being slid beyond the distal end of the elongated sleeve,when in the body.

[0024] Another embodiment is directed to a medical device having anelongated sleeve with a distal end and a proximal end, a trocarslideable within the elongated sleeve, the trocar including a distalsegment, and at least a portion of the distal segment slideable beyondthe distal end of the elongated sleeve. The trocar is formed of a shapememory material, and at least a portion of the distal segment of thetrocar has a preformed shape trained into it, for example a curvedshape, such that it assumes the preformed shape upon being slid beyondthe distal end of the elongated sleeve, when in the body.

[0025] Another embodiment is directed to a method for treating at leasta portion of the prostate, for example, the anterolateral portionobstructed by (typically behind) the pubic arch. The method involvesproviding an apparatus having an elongated sleeve with a distal end anda proximal end, a needle slideable within the elongated sleeve, theneedle including a distal segment, at least a portion of the distalsegment slideable beyond the distal end of the elongated sleeve; and theneedle being formed of a shape memory material, with a curved shapepreformed into at least the distal portion. The apparatus is then movedto a sufficient depth within the prostate in a direction from theperineum to the prostate, and at least a portion of the distal segmentis extended beyond the distal end of the elongated sleeve to the desiredsite within the prostate, such that upon contact with the prostatetissue, the needle returns (e.g., curving) to its preformed shape. Atleast one treatment element, for example, a seed or a spacer, is guidedthrough at least a portion of the needle to the desired site within theprostate.

[0026] Another embodiment is also directed to a method for treating atleast a portion of the prostate, for example, the anterolateral portionobstructed by the pubic arch. The method involves providing an apparatushaving an elongated sleeve with a distal end and a proximal end, aneedle slidable within the elongated sleeve, the needle including adistal segment, at least a portion of the distal segment slideablebeyond the distal end of the elongated sleeve, and the needle beingformed of a shape memory material, with a curved shape preformed into atleast the distal portion. At least one treatment element, for example, aseed or a spacer, is provided in the distal segment of the needle. Theapparatus is moved to a sufficient depth within the prostate in adirection from the perineum to the prostate. At least a portion of thedistal segment is extended beyond of the needle the distal end of theelongated sleeve to the desired site within the prostate, such that uponcontact with the prostate tissue, the needle returns to its preformedshape. The at least one treatment element is then guided through atleast a portion of the needle to the desired site within the prostate.

[0027] Another embodiment is directed to a method for treating at leasta portion of the prostate, for example, the anterolateral portionobstructed by the pubic arch. The method involves providing an apparatushaving an elongated sleeve with a distal end and a proximal end, aneedle slideable within the elongated sleeve, the needle including adistal segment at a distal end of the needle, at least a portion of thedistal segment slideable beyond the distal end of the elongated sleeve,and the needle being formed of a shape memory material, with a curvedshape preformed into at least the distal portion. The apparatus is movedto a sufficient depth within the prostate in a direction from theperineum to the prostate. At least a portion of the distal segment ofthe needle is extended beyond the distal end of the elongated sleeve tothe desired site within the prostate, such that upon contact with theprostate tissue, the needle returns to its preformed shape. Theelongated sleeve is removed from the body. A sheath is then moved overthe needle to a point proximate the distal end of the needle. The needleis removed from the body, and at least one treatment element, forexample, a seed or a spacer, is guided through at least a portion of thesheath to the desired site within the prostate.

[0028] Another embodiment is directed to a method for treating at leasta portion of the prostate, for example, the anterolateral portionobstructed by the pubic arch. The method involves providing an apparatushaving an elongated sleeve with a distal end and a proximal end, atrocar slideable within the elongated sleeve, the trocar including adistal segment at a distal end of the trocar, at least a portion of thedistal segment slideable beyond the distal end of the elongated sleeve,and the trocar being formed of a shape memory material, with a curvedshape preformed into at least the distal portion. The apparatus is movedto a sufficient depth within the prostate in a direction from theperineum to the prostate. At least a portion of the distal segment ofthe trocar is extended beyond the distal end of the elongated sleeve tothe desired site within the prostate, such that upon contact with theprostate tissue, the trocar returns to its preformed shape. Theelongated sleeve is removed from the body. A sheath is moved over thetrocar (for example, by sliding) to a point proximate the distal end ofthe trocar. The trocar is removed from the body, and at least onetreatment element, for example, a seed or a spacer, is guided through atleast a portion of the sheath to the desired site within the prostate.

[0029] Accordingly, several objects and advantages disclosed hereinprovide a means of avoiding pubic arch interference during prostatebrachytherapy, to provide a radiopaque needle or trocar, for use withimage-guidance during the brachytherapy procedure, to provide anMRI-compatible needle for use with MRI-guidance, to provide adeflectable implantation device which permits implementation of thebrachytherapy dosimetry plan to avoid underdosing lateral aspects of theprostate and overdosing more central aspects of the prostate, and toprovide a safe means of implanting prostates with larger volumes thanare presently considered technically feasible. Still further objects andadvantages will become apparent from a study of the followingdescription and accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Attention is now directed to the drawing figures, where likenumerals, or characters indicate corresponding or like components. Inthe drawings:

[0031]FIG. 1 is a schematic view, from the perineum, of the prostate inrelation to the pubic arch and the rectum;

[0032]FIG. 2A is a schematic cross-sectional view of the prostate andpubic arch of FIG. 1 with an implant needle traversing the templateneedle guide;

[0033]FIG. 2B is a schematic cross-sectional view of the prostate andpubic arch of FIGS. 1 and 2A with the implant needle traversing thetemplate needle guide through a different hole in the template;

[0034]FIG. 3 is a schematic cross-sectional view of a disclosedembodiment in an exemplary operation in the body;

[0035]FIGS. 4A and 4B are side views of the embodiment of the apparatusdisclosed in FIG. 3;

[0036]FIG. 5 is a perspective view of the hub portion of the needle;

[0037]FIG. 6 is a perspective view of the stylet of the apparatus ofFIG. 3;

[0038]FIGS. 7A and 7B are side views of a second embodiment of anapparatus;

[0039] FIGS. 8A-8C are diagrams detailing the operation of the apparatusof FIGS. 7A and 7B;

[0040]FIGS. 9A and 9B are side views of a third embodiment of anapparatus; and

[0041] FIGS. 10A-10F are diagrams showing the operation of the apparatusof FIGS. 9A and 9B.

DETAILED DESCRIPTION OF THE DRAWINGS

[0042]FIG. 3 shows the apparatus 100 disclosed herein in an exemplaryoperation (detailed below). Here, the apparatus 100 is such that theneedle 102 at its distal end, extends beyond the sleeve 104, such thatthe portion 102 a of the distal segment 102 b (FIG. 4B) of the needle102 beyond the sleeve 104 bends to its preformed or pretrained shape.This allows for treatment elements, for example, seeds 110 and spacers(or seeds 110 without spacers) to be deployed, for example adjacent oneanother and in rows (only one row shown for example only), in accordancewith the operator's treatment protocol, in the anterolateral portion 10a of the prostate 10, through the needle 102, in accordance withstandard brachytherapy procedures. A needle guide template 17 may beused for guiding the apparatus 100.

[0043]FIGS. 4A and 4B show the apparatus 100 prior to deployment. Thisapparatus 100 includes the needle 102, surrounded along a portion of itslength by a sleeve 104.

[0044] The needle 102 terminates in a tip 116, typically a bevel 117 ora point, at one end, and in a hub 118 at the other end. This tip 116 canbe, for example, echogenic. The hub 118 is dimensioned to receive a core120 of a stylet 122 (FIG. 5), in a frictional engagement, such that thecore 120 can be temporarily retained in the hub 118. The hub 118 istypically funnel-like in shape. It includes a grooved lip 124 (FIG. 6)on the side of the bevel 117, that coupled with the funnel-like shapefacilitates loading of the needle 102 with seeds.

[0045] The sleeve 104 has a flat edged opening 126 at one end, and acollar 128, extending around it at the other end. The collar 128typically includes ridges 129 to allow for ease in gripping of thesleeve 104.

[0046] Turning also to FIG. 6, the stylet 122 is dimensioned to extendthrough the needle 102 to at least the tip 116, and for example, to thepoint or bevel 117. The stylet 122 prevents the needle 102 from cloggingduring its deployment, as it prevents tissue from getting into the innerbore of the needle 102. This condition, where tissue gets into the innerbore of a needle as a result of its being open, is commonly known as“coring”. The stylet 122 is typically in frictional contact with theinner walls of the bore of the needle 102, while being slidable withinthe needle 102. The needle 102 is typically in frictional contact withthe inner walls of the sleeve 104, while being slideable within thesleeve 104.

[0047] The needle 102 is typically of a shape memory material such asnickel-titanium (Ni—Ti) or Nitinol®. Other suitable shape memorymaterials for the needle 102 can be, for example, Cu—Al—Ni, Cu—Zn—Al,Au—Cd, Mn—Cu, Ni—Mn—Ga. The needle 102 has a shape pretrained(preformed) into it, such that when it is in the body, it returns tothis pretrained shape. Here for example, the needle 102 is trained tobend, and in particular, the portion of the needle 102 a that extendsfrom the sleeve 104 can bend to various curvatures (as illustrated inbroken lines, and for example, rounded), as shown in FIG. 4B. Thisbending allows for accessing portions of the prostate 10 obstructed by(typically behind) the pubic arch 12, typically for seeding (as detailedherein).

[0048] The sleeve 104 is typically made of a surgical grade material,for use in the body. This material is typically rigid, so as to keep theportions of the needle 102 enclosed in the sleeve 104 in a straight orsubstantially straight orientation. The sleeve 104 can be made of, forexample, a surgical grade stainless steel, or a Magnetic ResonanceImaging (MRI) compatible material such as titanium, polymers,non-ferromagnetic alloys (e.g., INCONEL® and HASTELLOY®) or a materialthat incorporates nanotechnology, such as with carbon based nanotubes.The sleeve 104 can also be made from polymeric materials, for example,polyetheretherketone, such as PEEK®. The collar 126 is typically made ofthe same materials as the sleeve 104 and joined thereto by conventionalmaterials joining techniques.

[0049] The stylet 122 is typically flexible, so as to bend with theportion of the needle 102 that is extended out of the sleeve 104. Thestylet 122 is for example, made of the materials used for the sleeve104.

[0050] Reference will be made to FIGS. 3-6 to describe an exemplaryoperation for the apparatus 100. Initially, a viewing device, forexample, an ultrasound or MRI probe, is placed into the rectum 15(FIG. 1) for guiding the apparatus 100. The apparatus 100, as shown inFIGS. 4A, 4B, 5 and 6 is typically placed through a template or needleguide 17, and moved toward the prostate 10, as shown in FIG. 3. Duringthis advancement, the needle 102 is in a position where its tip 116, isproximate the sleeve opening 126 and the end of the stylet 122 isproximate to the needle tip 116, sitting slightly behind (proximal to)the bevel 117 in the needle bore (so the needle tip 116, in particular,the bevel 117 acts as the cutting edge with the stylet 122 deflectingtissue from the needle bore). The apparatus 100 is advanced to anappropriate depth, with its position confirmed by tactile factors feltby the clinician upon attaining penetration depths, coupled with imagingdata from the ultrasound or MRI probe.

[0051] The apparatus 100 may, for example, have a needle 102 that is 18gauge, while the sleeve 104 is of a 17 gauge. This allows the apparatus100 to be of a suitable gauge for seed (and spacers, if necessary)passage, while allowing it to be used with standard templates or needleguides, whose openings are typically configured for accommodating 17gauge instruments.

[0052] Once the apparatus 100 is at this position, such that theanterolateral portion 10 a of the prostate 10 is reachable by the needle102, a portion 102 a of the distal segment 102 b of the needle 102, andcorresponding portion of the stylet 122, are extended beyond the sleeve104. The needle 102 has been previously oriented by the clinician,typically by rotating it at the hub 118, such that it upon its releasefrom the sleeve 104, it bends, in accordance with the pretrained shape,to access the anterolateral portion 10 a of the prostate 10.

[0053] With access now attained, the stylet 122 is removed, typically bypulling on the core 120. Radioactive seeds 110 and spacers if desired,can now be loaded into the needle 102, through the hub 118. Seeds can befor example, capsule-like in shape, typically with a capsule of titaniumor stainless steel, for encapsulating a radioisotope. These seeds 110can be for example, I-125 or Pd-103 brachytherapy seeds, or otherconventional brachytherapy seeds. Other radioactive seeds, suitable foruse here, can be, for example, those detailed in PCT Patent ApplicationPCT/US01/43517, entitled: Polymeric Imagable Brachytherapy Seed, thisPCT patent application incorporated by reference herein. The capsule ofthese seeds is made of a biocompatible substance, such as polymericmaterials, and is tightly sealed to prevent leaching of theradioisotope. These aforementioned seeds for example, have diameters ofabout 0.8 mm and a length of about 4.5 mm, so as to fit in the bore ofan 18 gauge needle.

[0054] Exemplary radioactive seeds include Symmetra® I-125 (Bebig GmbH,Germany), IoGold™ I-125 and Pd-103 (North American Scientific,Chatsworth, Calif.), Best® I-125 and Best® Pd-103 (Best Industries,Springfield, Va.), Brachyseed® I-125 (Draximage, Inc., Canada),Intersource® Pd-103 (International Brachytherapy, Belgium), Oncoseed®I-125 (Nykomed Amersham, UK) STM 1250 I-125 (Sourcetech Medical, CarolStream, Ill.), Pharmaseed® I-125 (Syncor, Woodland Hills, Calif.),Prostaseed® I-125 (Urocor, Oklahoma City, Okla.) and I-plant® I-125(Implant Sciences Corporation, Wakefield, Mass.).

[0055] Alternately, the seeds can be non-radioactive. Thesenonradioactive seeds would typically be impregnated with drugs or thelike.

[0056] Spacers can be, for example, those described in PCT PatentApplication PCT/US01/43517, that is incorporated by reference herein.Spacers, can be, for example, of a biocompatible material that can beused to join two brachytherapy seeds. The biocompatible material can beeither biodegradable or non-biodegradable. These exemplary spacers canbe made of catgut or a like material. For example, Ethicon, Inc.(Cincinnati, Ohio) manufactures the PG 910 non-sterile autoclavablespacer for Indigo (Cincinnati, Ohio) that is sold in conjunction with anExpress Seed Cartridge. In addition, Medical Device Technologies, Inc.(Gainesville, Fla.) distributes a presterilized, 5.5 mm (in length)absorbable pre-cut spacer that is made of collagen (LOOK®, Model No.1514b). The spacers can also be of radiopaque materials.

[0057] The stylet 122 can now be inserted back into the needle 102, topush the seeds 110, and spacers if desired, for their placement at thedesired destination. Alternately, another stylet or blunt obterator canreplace the stylet 122 on reinsertion into the needle 102 and pushingand placement of the seeds 110 (and spacers). This seeding step can berepeated for as long as necessary.

[0058] Alternately, seeds (and spacers if desired) can be preloaded inthe apparatus 100. Here, a seed, of the desired amount of seeds andspacers (if desired), would be placed into the needle 102, so as to beat the needle tip 116. This seed serves to keep the needle bore closedto prevent coring (as detailed above). The stylet 122 or a bluntobterator would be in the needle 102 immediately following (or proximal)the seed(s) (and spacers, if necessary). All other needle positioningand seed (and spacer) deployment, would be in accordance with theprocedure detailed above.

[0059] Alternately, the aforementioned process can modified slightly forhigh dose rate (HDR) brachytherapy. In this process, once the needle 102has accessed the anterolateral portion of the prostate, an encapsulatedradioactive source, for example, an iridium-192 seed, may be driventhrough the needle 102 to the tip 116 with a mechanized cable or line.The seed would be permitted to dwell for a designated time period, andthen it would be retrieved by the same cable or line (typically by beingattached thereto).

[0060] Alternately, the guidance of the needle 102, sleeve 104, andstylet 122, can be by external imaging, for example CT or MRI. It canalso be by techniques, such as Fluoroscopy (as many materials for atleast the needle 102, and sleeve 104 are radiopaque by their generalnature, with other materials listed above for the needle 102 and sleeve104 easily modified to be radiopaque). The needle 102 can also be guidedby use of a look-up table or by a software program, in accordance withU.S. Pat. No. 6,368,331 (Front, et al.), this document incorporated byreference herein. Additionally, prior to entry into the body, the needle102 can be preheated, should the material of the needle be such thatthis external heating is required in addition to body heat to activatethe preformed (pretrained) configuration of the needle 102.

[0061]FIGS. 7A and 7B detail an alternate embodiment apparatus 100′ ofthe apparatus 100 detailed above. Here, the apparatus 100′ is similar inconstruction, arrangement and materials to apparatus 100, withidentically numbered components, except where indicated.

[0062] The apparatus 100′ includes a needle 102′ similar in all aspectsto needle 102, except that it either has a detachable, for example, aclip-on hub (not shown), or lacks a hub. This is because a sheath 150(FIGS. 8A-8C) is configured for being placed over the needle 102′ onceit is deployed to reach the target area of the prostate. A sleeve 104extends over the needle 102′, with a stylet 122 extending through theneedle 102, so as to prevent coring (as detailed above). A portion 102a′ of the distal segment 102 b′ of the needle 102′ extends beyond thesleeve 104, so as to curve in order to reach desired portions, forexample, the anterolateral portion 10 a of the prostate 10.

[0063] Turning also to FIGS. 8A-8C, an exemplary operation of theapparatus 100′ is detailed. Deployment of the apparatus 100′ underguidance of the clinician, through tactile factors (detailed above) andimaging data from the ultrasound or MRI probes, or external guidance, issimilar to that for apparatus 100 detailed above. During thisadvancement, the needle 102′ is in a position where its tip 116, isproximate the sleeve opening 126 and the end of the stylet 122 isproximate to the needle tip 116, similar to that for the apparatus 100above. Once the desired position for the sleeve 104 is attained, aportion 102 a′ of the needle 102′, with the corresponding portion of thestylet 122, is moved beyond the sleeve 104, with the needle 102′ havingthe position of the broken line portion of FIG. 7B.

[0064] With the needle 102′ in its desired position at the desireddepth, the stylet 122 is removed, by pulling it out of the needle 102′.The sleeve 104 is then removed, pulling it out of the body. Alternately,the sleeve 104 and stylet 122 can be removed together.

[0065] The sheath 150, typically made of a flexible polymer, that is,for example, MRI compatible, is then moved over the needle 102′, in thedirection of the arrow 152, as shown in FIG. 8A. The sheath 150typically includes a hub 154 (FIGS. 8B and 8C) at its proximal end toallow for easier gripping and retention by the clinician or operator.Movement of the sheath 150 continues until it is proximate the needletip 116, as shown in FIG. 8B. The needle 102′ is then removed from thesheath 150 (in the direction of the arrow 158), leaving an open path tothe prostate 10, in particular, the anterolateral portion 10 a thereof.The sheath 150 can also be of radiopaque polymers or radiopaque portionsthereof, or of materials modified to be radiopaque.

[0066] As shown in FIG. 8C, a seed 110 (as detailed above) is placedinto the sheath 150 and pushed toward the prostate 10 by a stylet 122 orblunt obturator (in the direction of the arrow 160). Pushing continuesuntil the seed 110 is properly positioned in the prostate 10. While asingle seed is shown, this is exemplary only, as the seed could bereplaced by multiple seeds and spacers (as detailed above) if desired.The procedure can be repeated as long as desired. With the procedurecomplete, the sheath 150 can be withdrawn from the body.

[0067] In this embodiment, the needle 102′, for example, may be lessthan 18 gauge, as it serves to create a pathway to the anterolateralportion 10 a of the prostate 10. For example, the sleeve 104 would be ofan inner diameter (bore) gauge greater than the needle, but not greaterthan 17 gauge, so as to fit within openings on a conventional templateor needle guide (typically configured for accommodating 17 gaugeinstruments, as detailed above). The sheath 150, for example, could be18 gauge or greater in order to accommodate seeds (and spacers, ifnecessary) while being able to easily slide over the needle 102′.

[0068] Alternately, the apparatus 100′ could be used in High Dose Rate(HDR) Brachytherapy. The process would be similar to that detailed forapparatus 100, above, except that the encapsulated radioactive sourcewould be driven down and retrieved through the sheath 150, instead ofthe needle 102.

[0069]FIGS. 9A and 9B show a third apparatus 200. This apparatus 200includes a trocar 202 and a cannula 204. The trocar 202 and cannula 204are dimensioned such that the trocar 202 can slide within the cannula204, such that a portion 202 a of a distal segment 202 b of the trocar202, can be extended beyond the cannula 204, in order that it bedeployed to the desired position (as detailed above).

[0070] The trocar 202 is a solid member, with a tip 212, for example,terminating in a point 214. Similar to the needle tip 116, detailedabove, this tip 212 can be echogenic. By being a solid member, thisprevents the cannula 204 from clogging during its deployment, as itprevents tissue from getting into the inner bore of the cannula 204, or“coring”. The trocar 202 is typically of a shape memory material such asnickel-titanium or Nitinol® (or any of the other materials listed forthe needle 102 above), with a shape, for example, a curvature (forexample, rounded), pretrained (preformed) into it (as shown by brokenlines in FIG. 9B). This way, when the trocar 202 is in the body, theportion 202 a extended beyond the cannula 204 returns to this pretrainedshape. This bending allows for accessing portions of the prostate 10behind the pubic arch 12, typically for seeding (as detailed herein).

[0071] The cannula 204 is similar to sleeve 104 above, in that it has aflat edged opening 216 at one end, and a collar 218, extending around itat the other end. The collar 218 typically includes ridges 219 to allowfor ease in gripping of the sleeve 204. The cannula 204 is of a materialthat is typically rigid, so as to keep the portions of the trocar 202enclosed therein, in a straight or substantially straight orientation.

[0072] The cannula 204 is typically made of a surgical grade material,for use in the body. This material is typically rigid, so as to keep theportions of the trocar 202 enclosed in the cannula 204 in a straight orsubstantially straight orientation. The cannula 204 can be made of, forexample, a surgical grade stainless steel, or a Magnetic ResonanceImaging (MRI) compatible material such as titanium, polymers,non-ferromagnetic alloys (e.g., INCONEL® and HASTELLOY®) or a materialthat incorporates nanotechnology, such as with carbon based nanotubes.The cannula 204 can also be made from polymeric materials, for example,polyetheretherketone, such as PEEK®. The collar 218 is typically made ofthe same materials as the cannula 204 and joined thereto by conventionalmaterials joining techniques.

[0073] The apparatus 200 also includes a sheath 220 (FIGS. 10B-10E) anda stylet 222 (FIGS. 10D and 10E). The sheath 220 is typically a flexiblesheath, similar to the sheath 150 detailed above, and is dimensioned toslide over the trocar 202, as it is placed over the trocar 202. Thestylet 222 includes a hub 224, and is similar to the stylet 122 detailedabove.

[0074] Turning now to FIGS. 10A-10F, an exemplary operation of theapparatus 200 is now described. Initially, a viewing device, forexample, an ultrasound or MRI probe, is placed into the rectum 15 (FIG.10A) for guiding the apparatus 200. Turning to FIG. 10A, the apparatus200, is typically placed through a template or needle guide 17, andmoved toward the prostate 10. The apparatus 200 is advanced to anappropriate depth, with its position confirmed by tactile factors feltby the clinician upon attaining penetration depths, coupled with imagingdata from the ultrasound or MRI probe. During this advancement, thetrocar 202′ is in a position where its tip 214, is proximate the sleeveopening 216.

[0075] Once the apparatus 200 is at this point, a portion 202 a of thetrocar 202 is extended beyond the cannula 204. The trocar 202 has beenpreviously oriented by the clinician, typically by rotating it, suchthat it upon its release from the cannula 204, it bends, in accordancewith the pretrained (preformed) shape, to reach the anterolateralportion 10 a of the prostate 10.

[0076] With the anteriorlateral portion 10 a of the prostate 10 reached,the cannula 204 is removed from the body. The flexible sheath 220 isadvanced over the trocar 202 to its tip 214, in the direction of thearrow 230, as shown in FIG. 10B. Advancement of the sheath 220 continuesuntil it reaches the tip 212 of the trocar 202, as shown in FIG. 10C.The trocar 202 is then removed from the flexible sheath 220, by beingslid out of the sheath 226 in a direction away from the body, inaccordance with the arrow 232.

[0077] The apparatus 200 may, for example, have a trocar 202 of an 18gauge size, while the sleeve 204 is of a 17 gauge size. This allows thefor the sheath 220 to be of, for example, a 17 gauge, and thus asuitable gauge for seed (and spacers, if necessary) passage.Additionally, all instrumentation can be used with standard templates orneedle guides, whose openings are typically configured for accommodating17 gauge instruments (detailed above).

[0078] In FIG. 10D, with access now to the anterolateral portion 10 a ofthe prostate 10 attained, radioactive seeds 110 (as detailed above) andspacers (as detailed above) if desired (one seed 110 shown asrepresentative of seeds and spacers, if desired), can now be loaded intothe sheath 220. The stylet 222 can now be placed into the sheath 220,and moved forward in the direction of the arrow 234. This forwardmovement moves the seeds 110 forward in the sheath 220, for theirplacement in the anteriorlateral portion 10 a of the prostate 10, asdetailed for apparatus 100 above, as shown in FIG. 10E. This seedingstep can be repeated for as long as necessary. Once seeding is complete,as shown in FIG. 10F, the sheath 220 is removed, leaving the seeds 110in place in the prostate 10, here the anterolateral portion 10 a.

[0079] Alternately, the apparatus 200 could be used in High Dose Rate(HDR) Brachytherapy. The process would be similar to that detailed forapparatus 100, 100′ above, except that the encapsulated radioactivesource would be driven down and retrieved through the sheath 220,instead of the needle 102, and sheath 150, respectively.

[0080] Alternately, the guidance of the trocar 202, sleeve 204, andsheath 220, can be by external imaging, for example CT or MRI. It canalso be by techniques, such as Fluoroscopy (as many materials for atleast the trocar 202 and sleeve 204 are by their general natureradiopaque, with other materials listed above for the trocar 202 andsleeve 204 easily modified to be radiopaque), as detailed for theapparatus 100 above. The trocar 202 can also be guided by use of alook-up table or by a software program, in accordance with U.S. Pat. No.6,368,331 (Front, et al.), as detailed for the apparatus 100 above,Additionally, prior to entry into the body, the trocar 202 can bepreheated, should the material of the trocar be such that this externalheating is required in addition to body heat to activate the preformed(pretrained) configuration of the trocar 102.

[0081] While the apparatus 100, 100′ and 200 above have been describedin association with brachytherapy procedures, this is exemplary only.The apparatus 100, 100′ and 200 could be used in any procedure, where itis necessary to bypass bone, or other tissue masses (hard or softtissue), organs, glands, or the like that may be in a the direct path ofan instrument, to access and/or treat the desired treatment site behindthe bypassed bone, tissue mass, organ, gland or the like. Whileexemplary treatments with treatment elements such as seeds, with andwithout spacers has been described, other treatment elements, forexample, those detailed in PCT Patent Application PCT/US01/43517, couldalso be employed with the apparatus 100, 100′ and 200, in similarmanners.

[0082] While preferred embodiments of systems, apparatus, components andmethods, have been described above, the description of the systems,apparatus, components and methods above is exemplary only. Those skilledin the art will recognize, or be able to ascertain using no more thanroutine experimentation, many equivalents to the specific embodiments ofthe invention described herein. Such equivalents are intended to beencompassed by the following claims.

What is claimed is:
 1. A medical device comprising: an elongated sleevewith a distal end and a proximal end; a needle slidable within theelongated sleeve, the needle including a distal segment, at least aportion of the distal segment slideable beyond the distal end of theelongated sleeve; the needle being formed of a shape memory material;and the distal segment of the needle having a preformed shape trainedinto it such that it assumes the preformed shape upon being slid beyondthe distal end of the elongated sleeve in the body.
 2. The device ofclaim 1, wherein the preformed shape is curved.
 3. The device of claim1, wherein the needle includes an inner bore dimensioned to accommodatethe passage of at least one brachytherapy seed therethrough.
 4. Thedevice according of claim 3, wherein the inner bore is dimensioned toaccommodate I-125 or Pd-103 brachytherapy seeds.
 5. The device of claim1, wherein the shape memory material includes a nickel-titanium alloy.6. The device of claim 3, wherein the inner bore of the needle is 17 or18 gauge.
 7. The device of claim 1, wherein the needle includes at leastone beveled edge.
 8. The device of claim 7, wherein the needle includesat least one hub, the hub including a grooved lip at a substantiallysimilar orientation as the at least one beveled edge.
 9. The device ofclaim 3, additionally comprising a stylet slidably received in the innerbore.
 10. The device of claim 1, wherein the needle includes an innerbore.
 11. The device of claim 10, additionally comprising a styletslidably received in the inner bore.
 12. The device of claim 10,additionally comprising a sheath configured for sliding over the needle.13. The device of claim 12, wherein the sheath includes an inner boredimensioned to accommodate the passage of at least one brachytherapyseed therethrough.
 14. The device of claim 13, wherein the inner bore isdimensioned to accommodate I-125 or Pd-103 brachytherapy seeds.
 15. Thedevice of claim 12, wherein the sheath is of a flexible material.
 16. Amedical device comprising: an elongated sleeve with a distal end and aproximal end; a leading member slidable within the elongated sleeve, theleading member including a distal segment, at least a portion of adistal segment slideable beyond the distal end of the elongated sleeve;the leading member being formed of a shape memory material; and the atleast a portion of the distal segment of the leading member having apreformed shape trained into it such that it assumes the preformed shapeupon being slid beyond the distal end of the elongated sleeve in thebody.
 17. The device of claim 16, wherein the leading member includes atrocar.
 18. The device of claim 17, wherein the preformed shape iscurved.
 19. The device of claim 17, wherein the shape memory materialincludes a nickel-titanium alloy.
 20. The device of claim 17, whereinthe trocar is 17 or 18 gauge.
 21. The device of claim 17, additionallycomprising a sheath configured for sliding over the trocar.
 22. Thedevice of claim 21, wherein the sheath includes an inner boredimensioned to accommodate the passage of at least one brachytherapyseed therethrough.
 23. The device of claim 22, wherein the inner bore isdimensioned to accommodate I-125 or Pd-103 brachytherapy seeds.
 24. Thedevice of claim 21, wherein the sheath is of a flexible material. 25.The device of claim 16, wherein the leading member includes a needle.26. The device of claim 16, wherein the needle includes an inner boredimensioned to accommodate the passage of at least one brachytherapyseed therethrough.
 27. The device of claim 26, wherein the inner bore isdimensioned to accommodate I-125 or Pd-103 brachytherapy seeds.
 28. Thedevice of claim 25, wherein the shape memory material includes anickel-titanium alloy.
 29. The device of claim 26, wherein the innerbore of the needle is 17 or 18 gauge.
 30. The device of claim 25,wherein the needle includes at least one beveled edge.
 31. The device ofclaim 30, wherein the needle includes at least one hub, the hubincluding a grooved lip at a substantially similar orientation as the atleast one beveled edge.
 32. The device of claim 26, additionallycomprising a stylet slidably received in the inner bore.
 33. The deviceof claim 25, wherein the needle includes an inner bore.
 34. The deviceof claim 13, additionally comprising a stylet slidably received in theinner bore.
 35. The device of claim 25, additionally comprising a sheathconfigured for sliding over the needle.
 36. The device of claim 35,wherein the sheath includes an inner bore dimensioned to accommodate thepassage of at least one brachytherapy seed therethrough.
 37. The deviceof claim 36, wherein the inner bore is dimensioned to accommodate I-125or Pd-103 brachytherapy seeds.
 38. The device of claim 35, wherein thesheath is of a flexible material.
 39. A medical device comprising: anelongated sleeve with a distal end and a proximal end; a trocar slidablewithin the elongated sleeve, the trocar including a distal segment, atleast a portion of the distal segment slideable beyond the distal end ofthe elongated sleeve; the trocar being formed of a shape memorymaterial; and the at least a portion of the distal segment of the trocarhaving a preformed shape trained into it such that it assumes thepreformed shape upon being slid beyond the distal end of the elongatedsleeve in the body.
 40. The device of claim 39, wherein the preformedshape is curved.
 41. The device of claim 40, wherein the shape memorymaterial includes a nickel-titanium alloy.
 42. The device of claim 39,wherein the trocar is 17 or 18 gauge.
 43. The device of claim 39,additionally comprising a sheath configured for sliding over the needle.44. The device of claim 43, wherein the sheath includes an inner boredimensioned to accommodate the passage of at least one brachytherapyseed therethrough.
 45. The device of claim 44, wherein the inner bore isdimensioned to accommodate I-125 or Pd-103 brachytherapy seeds.
 46. Thedevice of claim 43, wherein the sheath is of a flexible material.
 47. Amethod for treating at least a portion of the prostate comprising: a)providing an apparatus comprising: an elongated sleeve with a distal endand a proximal end; a needle slidable within the elongated sleeve, theneedle including a distal segment, at least a portion of the distalsegment slideable beyond the distal end of the elongated sleeve; and theneedle being formed of a shape memory material, with a curved shapepreformed into at least the distal portion; b) moving the apparatus to asufficient depth within the prostate in a direction from the perineum tothe prostate; c) extending at least a portion of the distal segmentbeyond the distal end of the elongated sleeve to the desired site withinthe prostate, such that upon contact with the prostate tissue, theneedle returns to its preformed shape; and d) guiding at least onetreatment element through at least a portion of the needle to thedesired site within the prostate.
 48. The method of claim 47, whereinthe step of providing an apparatus includes, providing a styletslideable within the needle.
 49. The method of claim 47, wherein movingthe apparatus to a sufficient depth within the prostate includes movingthe apparatus to a point at or beyond the pubic arch.
 50. The method ofclaim 49, additionally comprising, orienting the needle such that theneedle returns to its preformed shape at the anterolateral portion ofthe prostate.
 51. The method of claim 48, wherein step (c) additionallycomprises: removing the stylet from the needle.
 52. The method of claim51, wherein step (d) additionally comprises: placing the at least onetreatment element into the needle; and pushing the at least onetreatment element through the needle to the desired site within theprostate by inserting an instrument into the needle.
 53. The method ofclaim 52, wherein the at least one treatment element is at least oneseed.
 54. The method of claim 52, wherein the at least one treatmentelement is at least one spacer.
 55. A method for treating at least aportion of the prostate comprising: a) providing an apparatuscomprising: an elongated sleeve with a distal end and a proximal end; aneedle slidable within the elongated sleeve, the needle including adistal segment, at least a portion of the distal segment slideablebeyond the distal end of the elongated sleeve; and the needle beingformed of a shape memory material, with a curved shape preformed into atleast the distal portion; b) providing at least one treatment element inthe distal segment of the needle; c) moving the apparatus to asufficient depth within the prostate in a direction from the perineum tothe prostate; d) extending at least a portion of the distal segmentbeyond of the needle the distal end of the elongated sleeve to thedesired site within the prostate, such that upon contact with theprostate tissue, the needle returns to its preformed shape; and e)guiding the at least one treatment element through at least a portion ofthe needle to the desired site within the prostate.
 56. The method ofclaim 55, wherein the step of providing an apparatus includes, providinga stylet slideable within the needle.
 57. The method of claim 55,wherein a moving the apparatus to a sufficient depth within the prostateincludes moving the apparatus to a point at or beyond the pubic arch.58. The method of claim 57, additionally comprising, orienting theneedle such that the needle returns to its preformed shape at theanterolateral portion of the prostate.
 59. The method of claim 51,wherein step (e) includes: pushing the stylet in the needle to push theat least one treatment element to the desired site within the prostate.60. The method of claim 59, wherein the at least one treatment elementis at least one seed.
 61. The method of claim 59, wherein the at leastone treatment element is at least one spacer.
 62. A method for treatingat least a portion of the prostate comprising: a) providing an apparatuscomprising: an elongated sleeve with a distal end and a proximal end; aneedle slidable within the elongated sleeve, the needle including adistal segment at a distal end of the needle, at least a portion of thedistal segment slideable beyond the distal end of the elongated sleeve;and the needle being formed of a shape memory material, with a curvedshape preformed into at least the distal portion; b) moving theapparatus to a sufficient depth within the prostate in a direction fromthe perineum to the prostate; c) extending at least a portion of thedistal segment of the needle beyond the distal end of the elongatedsleeve to the desired site within the prostate, such that upon contactwith the prostate tissue, the needle returns to its preformed shape; d)removing the elongated sleeve from the body; e) moving a sheath over theneedle to a point proximate the distal end of the needle; f) removingthe needle from the body; and g) guiding at least one treatment elementthrough at least a portion of the sheath to the desired site within theprostate.
 63. The method of claim 62, wherein the step of providing anapparatus includes, providing a stylet slideable within the needle. 64.The method of claim 62, wherein a moving the apparatus to a sufficientdepth within the prostate includes moving the apparatus to a point at orbeyond the pubic arch.
 65. The method of claim 64, additionallycomprising, orienting the needle such that the needle returns to itspreformed shape at the anterolateral portion of the prostate.
 66. Themethod of claim 63, wherein step (f) includes: removing the stylet fromthe body.
 67. The method of claim 62, wherein step (g) additionallycomprises: placing the at least one treatment element into the sheath;and pushing the at least one treatment element through the sheath to thedesired site within the prostate by inserting an instrument into thesheath.
 68. The method of claim 67, wherein the at least one treatmentelement is at least one seed.
 69. The method of claim 67, wherein the atleast one treatment element is at least one spacer.
 70. A method fortreating at least a portion of the prostate comprising: a) providing anapparatus comprising: an elongated sleeve with a distal end and aproximal end; a trocar slidable within the elongated sleeve, the trocarincluding a distal segment at a distal end of the trocar, at least aportion of the distal segment slideable beyond the distal end of theelongated sleeve; and the trocar being formed of a shape memorymaterial, with a curved shape preformed into at least the distalportion; b) moving the apparatus to a sufficient depth within theprostate in a direction from the perineum to the prostate; c) extendingat least a portion of the distal segment of the trocar beyond the distalend of the elongated sleeve to the desired site within the prostate,such that upon contact with the prostate tissue, the trocar returns toits preformed shape; d) removing the elongated sleeve from the body; e)moving a sheath over the trocar to a point proximate the distal end ofthe trocar; f) removing the trocar from the body; and g) guiding atleast one treatment element through at least a portion of the sheath tothe desired site within the prostate.
 71. The method of claim 70,wherein a moving the apparatus to a sufficient depth within the prostateincludes moving the apparatus to a point at or beyond the pubic arch.72. The method of claim 71, additionally comprising, orienting thetrocar such that the trocar returns to its preformed shape at theanterolateral portion of the prostate.
 73. The method of claim 70,wherein step (g) additionally comprises: placing the at least onetreatment element into the sheath; and pushing the at least onetreatment element through the sheath to the desired site within theprostate by inserting an instrument into the sheath.
 74. The method ofclaim 73, wherein the at least one treatment element is at least oneseed.
 75. The method of claim 73, wherein the at least one treatmentelement is at least one spacer.